U.S. patent application number 12/637059 was filed with the patent office on 2011-09-01 for hydraulic assembly and hydraulic valve for forming said assembly.
This patent application is currently assigned to SCHAEFFLER KG. Invention is credited to Steffen Alvermann, Thomas Kramer, Henrik Meinel, Marco Meisborn, Johannes Weninger.
Application Number | 20110209677 12/637059 |
Document ID | / |
Family ID | 42101892 |
Filed Date | 2011-09-01 |
United States Patent
Application |
20110209677 |
Kind Code |
A1 |
Kramer; Thomas ; et
al. |
September 1, 2011 |
HYDRAULIC ASSEMBLY AND HYDRAULIC VALVE FOR FORMING SAID
ASSEMBLY
Abstract
A hydraulic assembly (1), particularly for an electrohydraulic
valve control of an internal combustion engine, and a hydraulic
valve (2) for forming such an assembly are provided. The assembly
includes a hydraulic valve with a valve housing (4) and a valve
carrier (3) with a valve receiver (5) in which the valve housing is
received. The valve housing has a first circumferential groove (9)
and a second circumferential groove (10), with the grooves (9 and
10) being defined respectively by groove walls (13, 15 and 14, 16)
and extending on two sides of a hydraulic connection (6) which
extends through a peripheral wall of the valve housing (4). A bead
(11, 12) formed by a plastic deformation of material of the valve
carrier being received in each of the two said grooves (9, 10), so
that the groove walls and the beads not only fix the valve housing
in the valve receiver by positive engagement but also cooperate
with each other to hydraulically seal the valve housing. Outer
groove walls of the circumferential grooves are oriented towards
each other and extend parallel to each other and perpendicularly to
the receiving direction of the valve housing.
Inventors: |
Kramer; Thomas; (Rothenbach,
DE) ; Meisborn; Marco; (Hochstadt a.d. Aisch, DE)
; Alvermann; Steffen; (Essen, DE) ; Weninger;
Johannes; (Gerhardshofen, DE) ; Meinel; Henrik;
(Herzogenaurach, DE) |
Assignee: |
SCHAEFFLER KG
Herzogenaurach
DE
|
Family ID: |
42101892 |
Appl. No.: |
12/637059 |
Filed: |
December 14, 2009 |
Current U.S.
Class: |
123/90.12 ;
251/366 |
Current CPC
Class: |
F01L 2001/34426
20130101; F16K 31/06 20130101; F16K 27/02 20130101; F01L 1/34
20130101; F01L 13/00 20130101 |
Class at
Publication: |
123/90.12 ;
251/366 |
International
Class: |
F01L 9/02 20060101
F01L009/02; F16K 27/00 20060101 F16K027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2008 |
DE |
102008062166.8 |
Claims
1. A hydraulic assembly for an electrohydraulic valve control of an
internal combustion engine, the assembly comprising a hydraulic
valve including a valve housing and a valve carrier including a
valve receiver in which the valve housing is received, the valve
carrier possessing, at least in a region of the valve receiver, a
distinctly lower material strength than the valve housing, the
valve housing including a first circumferential groove and a second
circumferential groove, the grooves being defined respectively by
groove walls and extending on two sides of a hydraulic connection
which extends through a peripheral wall of the valve housing and is
in hydraulic communication with a hydraulic channel which is
arranged in the valve carrier and opens into the valve receiver, a
bead formed by a plastic deformation of material of the valve
carrier being received in each of the first and the second grooves,
so that, in a receiving direction of the valve housing, the groove
walls and the beads not only fix the valve housing in the valve
receiver by positive engagement but also cooperate with each other
to hydraulically seal the valve housing, and outer ones of the
groove walls of the circumferential grooves are oriented towards
each other and extend parallel to each other and perpendicularly to
the receiving direction of the valve housing.
2. A hydraulic assembly of claim 1, wherein inner ones of the
groove walls of the circumferential grooves face away from each
other and extend parallel to each other and perpendicularly to the
receiving direction of the valve housing.
3. A hydraulic assembly of claim 2, wherein the circumferential
grooves comprise a substantially rectangular cross-section.
4. A hydraulic valve for forming a hydraulic assembly comprising
the hydraulic valve and a valve carrier, the hydraulic valve
including a valve housing that can be fixed by positive engagement
in a valve receiver of the valve carrier, the valve housing
including a first circumferential groove and a second
circumferential groove, the grooves being defined respectively by
groove walls and extending on two sides of a hydraulic connection
which extends through a peripheral wall of the valve housing, and
each of the grooves being configured to receive a bead formed by a
plastic deformation of material of the valve carrier, wherein outer
ones of the groove walls of the circumferential grooves are
oriented towards each other and extend parallel to each other and
perpendicularly to a receiving direction of the valve housing.
5. A hydraulic valve of claim 4, wherein inner ones of the groove
walls of the circumferential grooves face away from each other and
extend parallel to each other and perpendicularly to the receiving
direction of the valve housing.
6. A hydraulic valve of claim 5, wherein the circumferential
grooves comprise a substantially rectangular cross-section.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of German Patent
application DE 10 2008 062 166.8, filed Dec. 13, 2008, which is
incorporated herein by reference as if fully set forth.
BACKGROUND
[0002] The invention concerns a hydraulic assembly, particularly
for an electrohydraulic valve control of an internal combustion
engine, and a hydraulic valve for forming such an assembly. This
assembly comprises a hydraulic valve comprising a valve housing and
a valve carrier with a valve receiver in which the valve housing is
received. At least in the region of the valve receiver, the valve
carrier has a distinctly lower material strength than the valve
housing in which are disposed a first and a second circumferential
groove defined respectively by groove walls and extending on both
sides of a hydraulic connection which extends through a peripheral
wall of the valve housing and is in hydraulic communication with a
hydraulic channel which is arranged in the valve carrier and opens
into the valve receiver, a bead formed by a plastic deformation of
material of the valve carrier being received in each of the first
and the second circumferential grooves, so that, in a receiving
direction of the valve housing, the groove walls and the beads not
only fix the valve housing in the valve receiver by positive
engagement but also cooperate with each other to hydraulically seal
the valve housing.
[0003] An assembly of the above-noted type is disclosed in the
document DE 44 14 583 A1. The fixing of the valve housing in the
valve receiver by positive engagement is realized through a calking
method, designated hereinafter as clinched connection, which takes
place automatically during assembly of the hydraulic valve and the
valve carrier. For this purpose, the peripheries of the valve
housing and the valve receiver comprise in the region of the
circumferential grooves, stepped diameters that are matched to each
other such that the material of the valve carrier displaced by the
harder material of valve housing, which acts as a calking die,
flows into the circumferential grooves and gets compressed to form
beads within these grooves. To improve the material flow, the cited
prior art and also common practice proposes to configure the
circumferential grooves in the form of chamfered grooves, i.e. with
one inclined groove wall on the smaller diameter-side in assembling
direction.
[0004] However, this structural design can prove to be problematic
with respect to the hydraulic sealing function of the beads pressed
into the circumferential grooves if the different materials of the
valve carrier and valve housing have considerably differing thermal
expansion coefficients and the assembly is exposed to large
temperature variations in operation. This is particularly true if,
on the one hand, the known material pairing for the clinched
connection, viz., a valve carrier made of an aluminum material and
a valve housing made of a steel material, is used and, on the other
hand, the assembly is a part of the above-noted electrohydraulic
valve control of an internal combustion engine where its operation
has to be guaranteed for a temperature range of -30.degree. C. to
150.degree. C., which is typically specified for valve controls in
which sealing is required at peak hydraulic medium pressures of
about 150 bars. The reason for this is that, in the low temperature
range, the periphery of the valve receiver contracts distinctly
more strongly than the periphery of the valve housing, so that, in
this case, excellent sealing contacts are achieved both inside and
outside of the circumferential grooves, but conversely, in the high
temperature range, a circumferential gap can be formed between the
comparatively strongly expanding valve receiver and the valve
housing. The sealing effect of the clinched connection can then
only be maintained through the relative expansion of the valve
receiver in receiving direction of the valve housing in that the
beads press against the two outer, oppositely oriented groove walls
of the circumferential grooves.
[0005] As explained more clearly below with reference to the
appended figures, the maximal achievable pressing force, however,
depends substantially on the configuration of the chamfered
circumferential grooves. Specifically, in the region of the groove
wall inclinations that favor material flow, there exists a risk of
inadequate normal forces and, consequently, also of an inadequate
sealing effect between bead and groove wall.
SUMMARY
[0006] It is therefore an object of the invention to improve a
hydraulic assembly of the above-noted type and a hydraulic valve
for forming such an assembly, so that the aforesaid drawbacks are
overcome with simple means. The clinched connection should produce
an adequate sealing effect in the entire operational temperature
and pressure ranges of the assembly in order to prevent leakage of
hydraulic medium in the receiving direction of the valve house, at
least substantially.
[0007] This and other objects and advantages of the invention will
become obvious from the following detailed description.
[0008] According to the invention, the circumferential grooves
comprise outer groove walls that are oriented towards each other
and extend parallel to each other and perpendicularly to the
receiving direction of the valve housing. By outer groove walls are
to be understood one groove wall of the first circumferential
groove and one groove wall of the second circumferential groove
which are spaced furthest away from each other while being oriented
towards each other.
[0009] In other words, the invention is based on a conscious
reversal of the hitherto usual design of the circumferential
grooves all of which have a chamfered groove configuration in the
assembly direction, in order to assure an adequate sealing effect
of the clinched connection even in the upper operational
temperature range of the assembly. The considerably enhanced
sealing action at high temperatures is achieved by the fact that
the beads, which distance themselves more strongly from each other
than the circumferential grooves in the receiving direction of the
valve housing, apply high normal forces on the two outer groove
walls of the circumferential grooves which, together with the
concomitant, correspondingly higher contact pressures, produce a
strong sealing effect.
[0010] According to a further development of the invention, the
oppositely oriented inner groove walls of the circumferential
grooves likewise extend parallel to each other and perpendicularly
to the receiving direction of the valve housing. Analogously to the
above explanation, by inner groove walls are to be understood the
other groove wall of the first circumferential groove and the other
groove wall of the second circumferential groove which are situated
nearest to each other while facing away from each other.
[0011] While the configuration of the groove bottom which connects
the groove walls to each other, i.e. the surface of the
circumferential groove which is directed in the circumferential
direction of the valve housing, can be at least substantially
freely chosen and can have, for example, a circular arc shape, the
circumferential grooves must have a substantially rectangular
cross-section.
[0012] In connection with this, suitable tests carried out by the
applicant on components have surprisingly shown that even in the
case of circumferential grooves with a rectangular cross-section,
an adequate bead volume for fixing the valve housing in the valve
receiver by positive engagement can flow into the circumferential
grooves and get compressed therein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Further features of the invention will result from the
following description given with reference to the appended figures
with partially schematic representations showing an exemplary
embodiment of the invention with the help of which the inventive
sealing effect is further elucidated. If not otherwise specified,
identical or functionally identical features or components are
identified by the same reference numerals. The figures show:
[0014] FIG. 1 is a partial section view of a hydraulic assembly
comprising a valve carrier with a hydraulic valve fixed therein by
a clinched connection;
[0015] FIG. 2 is a longitudinal section view of the hydraulic valve
of FIG. 1;
[0016] FIG. 3 is an enlarged longitudinal section view of a
clinched connection of the invention comprising rectangular
circumferential grooves;
[0017] FIG. 4 is the detail Z of FIG. 3, in a further enlarged
representation,
[0018] and, schematically represented in each case:
[0019] FIG. 5 is a diagram of the force conditions at the inventive
clinched connection of FIG. 3, at -30.degree. C.;
[0020] FIG. 6 is a diagram of the force conditions at the inventive
clinched connection of FIG. 3, at 150.degree. C.;
[0021] FIG. 7 is a diagram of the force conditions at an inventive
clinched connection comprising trapezium-shaped circumferential
grooves, at 150.degree. C.;
[0022] FIG. 8 is a diagram of the force conditions for a prior art
clinched connection, at 30.degree. C., and
[0023] FIG. 9 is a diagram of the force conditions at the prior art
clinched connection, at 150.degree. C.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] FIG. 1 discloses a hydraulic assembly 1 that is comprised of
a hydraulic valve 2 and a valve carrier 3. The hydraulic valve 2
comprises a valve housing 4 made of a steel material and having a
circular cross-section which is received in a cylindrical valve
receiver 5 of the valve carrier 3, which, in the present case, is
made entirely of an aluminum material and inseparably fixed through
a clinched connection by positive engagement in the valve carrier
3. The hydraulic valve 2 represented in greater detail in FIG. 2 is
an electrically controlled 2/2 directional switching valve of a
type known, per se, which, together with the valve carrier 3 forms
a part of a likewise known electrohydraulic valve control device of
an internal combustion engine comprising variably operated gas
exchange valves.
[0025] The first hydraulic connection 6 extends through the
peripheral wall of the valve housing 4 and the second hydraulic
connection 7 extends on a front end of the valve housing 4 on the
bottom of the valve receiver 5. The hydraulic connection 6 is in
hydraulic communication with a hydraulic channel 8 which is
arranged in the valve carrier 3 and opens into the valve receiver 5
while extending between two circumferential grooves 9 and 10 which
are required for realizing the clinched connection (for the sake of
better perception, the circumferential grooves 9, 10 have been
shown on an exaggeratedly large scale but in reality they have a
distinctly smaller cross-section).
[0026] As already mentioned above, in the present context, the term
clinched connection is to be understood as a plastic deformation of
material of the valve carrier 3 which possesses a relatively low
material strength. The material deformation is produced during the
insertion of the valve housing 4, which acts as a calking die, into
the valve receiver 5, and the displaced material of the valve
carrier 3 flows into the circumferential grooves 9, 10 to get
compressed therein.
[0027] The finished clinched connection is disclosed in a
simplified illustration in FIG. 3 and also as an enlarged detail Z
in FIG. 4. The positive engagement realized through the beads 11
and 12 serves both for a durable fixing of the valve housing 4 in
the valve carrier 3 and for hydraulic sealing of the hydraulic
connection 6 in receiving direction of the valve housing 4, i.e.
sealing from the surrounding of the valve carrier 3 and from the
front-end hydraulic connection 7. The action of the valve housing 4
as a calking die requires certain design features with regard to
the diameter and length ratios on the periphery of the valve
housing 4 and the valve receiver 5, both of which have a stepped
diameter. These design features are basically known from the prior
art, so that there is no need to describe them further in the
present context.
[0028] FIGS. 8 and 9 show, symbolized by double arrows, the contact
forces decisive for the sealing effect in a hitherto usual clinched
connection comprising the circumferential grooves 9, 10 arranged on
both sides of the hydraulic connection 6, not shown, in a schematic
representation, at two extreme operational temperatures of the
assembly, i.e. at -30.degree. C. and 150.degree. C. In this prior
art clinched connection, the valve housing 4 comprises chamfered
circumferential grooves 9, 10 in which the plastically deformed
material of the valve carrier 3 formed into beads 11, 12 is
received.
[0029] At -30.degree. C., the sealing effect of the clinched
connection fabricated at an ambient temperature of about 20.degree.
C. is produced, both inside and outside of the circumferential
grooves 9, 10, in the first place, by contact forces acting in a
peripheral direction because, as a result of the different thermal
expansion coefficients of aluminum material and steel material, the
diameter of the valve receiver 5 contracts much more strongly than
that of the valve housing 4.
[0030] But, as a result of the opposite relative expansion at
150.degree. C., there exists the possibility of these contact
forces being fully neutralized and, in the extreme case represented
here, a circumferential gap can be formed between the valve
receiver 5 and the valve housing 4. In this case, the sealing
effect of the clinched connection can only be maintained through
the contact forces acting in receiving direction of the valve
housing 4 on the outer groove walls 13 and 14 of the
circumferential grooves 9 and 10, respectively, oriented towards
each other. These contact forces likewise result from the
temperature-related relative expansion of the valve carrier 3
compared to the valve housing 4 in the receiving direction thereof.
However, due to the inclination of the outer groove wall 14 in the
receiving direction, the normal force acting on this groove wall 14
is substantially reduced, so that, as a result, the sealing effect
relative to the bead 12 can be greatly impaired.
[0031] FIGS. 5 and 6 show a clinched connection of the present
invention in an illustration corresponding to FIGS. 8 and 9. The
modification made to the prior art clinched connection is
cost-neutral but extremely efficient with regard to the sealing
effect and concerns the geometric configuration of the
circumferential grooves 9 and 10, i.e. not only the outer groove
walls 13 and 14 but also the inner groove walls 15 and 16, which
are turned away from each other, are all parallel to one another
and perpendicular to the receiving direction of the valve housing
4. In conjunction with a cylindrical groove bottom 17, both the
circumferential grooves 9 and 10 have a rectangular
cross-section.
[0032] The sealing effect at -30.degree. C., which remains
excellent also in this modification, is additionally enhanced by
the contact forces that act in receiving direction and with which
the inner groove walls 15, 16 are loaded as a result of the
temperature-related relative contraction of the valve carrier 3
compared to the valve housing 4. As elucidated above, a result of
the opposed relative expansion at 150.degree. C. can be that the
sealing effect of the clinched connection can then be maintained
only through the contact forces acting in receiving direction on
the outer groove walls 13, 14. However, the inventive, modified
shape of the circumferential grooves 9, 10 leads to substantially
higher normal forces on the outer groove walls 13, 14 and, thus, to
hydraulically adequate sealing contact pressures relative to the
beads 11 and 12.
[0033] An alternative embodiment of a clinched connection is
disclosed in FIG. 7, likewise showing contact forces at 150.degree.
C. In this embodiment, the modification of the prior art clinched
connection is restricted substantially to the trapezium-shaped
configuration of the circumferential groove 10 on the side of the
second hydraulic connection 7. In this case, too, an essential
inventive feature is that the circumferential grooves 9 and 10
comprise outer groove walls 13, 14 that are oriented towards each
other and extend parallel to each other and perpendicularly to the
receiving direction of the valve housing 4 in order to guarantee an
adequate sealing effect of the clinched connection even at a high
temperature.
REFERENCE NUMERALS
[0034] 1 Hydraulic assembly [0035] 2 Hydraulic valve [0036] 3 Valve
carrier [0037] 4 Valve housing [0038] 5 Valve receiver [0039] 6
First hydraulic connection [0040] 7 Second hydraulic connection
[0041] 8 Hydraulic channel [0042] 9 Circumferential groove [0043]
10 Circumferential groove [0044] 11 Bead [0045] 12 Bead [0046] 13
Outer groove wall [0047] 14 Outer groove wall [0048] 15 Inner
groove wall [0049] 16 Inner groove wall [0050] 17 Groove bottom
* * * * *